Wai-o-tapu is about twenty minutes south of Rotorua on the road between Rotorua and Taupo. This does have a geyser present on the park but it is artificially stimulated around 10am each day to provide a display. Pohutu outclasses that easily. However what this park offers is coloured lakes, sulphur deposits, terrace formation and has a very famous set of mudpools just to the north of the main park itself.
I really liked the layout of this park - you had the main visitor centre with cafe but once in the park the paths and fencing were largely kept to a minimum. Even better someone had put a great deal of though into placing seats that overlooked most features allowing you to sit and watch a particular one easily. Mark and I both got quite entranced watching a pale blue pool churn and burble nicely on one of these seats. It also has a spectacular growth of sulphur crystals where a partial cave shelters the vent from the weather and has allowed them to grow to a remarkable size.
While this doesn't have the dramatic spectacle of something like Pohutu geyser it however has a definite beauty unto itself. The champagne lake with its strongly green water and a sublime light red border steaming away is amazing. It reinforces the volcanic nature of the ground you are walking on and it can be a little disturbing to notice that there are ledges of crust that you walk over that have boiling water a scant distance below.